Hitherto, there have been practiced a number of air treatments by various means, for example, removal of ozone from ozone-containing air by ozone-decomposing means using an ozone decomposition catalyst, deodorizing of odoriferous air by odor-eliminating means using a deodorant, dehumidification of moist air by hygroscopic means using a drying agent, removal of dust from air containing tobacco smoke or the like by adsorptive removal means using an adsorbent, and addition of fragrance to air by fragrance-releasing means using a fragrant agent.
In some cases, the catalyst, deodorant, drying agent, fragrant agent, adsorbent or the like having the function of treating air as above is formed in a honeycomb shape and disposed in a stream of air to achieve the desired treatment. In other cases, surfaces of a sirocco fan or axial fan used for blowing air are coated with the deodorant or the like having the air-treating function, or, alternatively, the sirocco fan or axial fan itself is formed of a material having a drying function.
The conventional air treatment processes, however, had the following problems.
First, where a deodorant or the like having an air-treating function and formed in a honeycomb shape is placed in a stream of air so as to treat the air, in general, an improvement in the air-treating function per unit volume of the honeycomb-shaped deodorant or the like requires either a marked narrowing of the passage space in the honeycomb (so-called honeycomb pitch) to increase the surface area of the deodorant or the like, or an increase in the length of the passage formed by the honeycomb-shaped deodorant or the like to prolong the dwell time of air in contact with the deodorant or the like. The narrowing of the passage space involves an increase in the passage resistance in the honeycomb-shaped deodorant or the like, leading to the need for a higher fan capacity. An increase in fan capacity requires either a higher rotational frequency, which results in greater noise, or a larger fan size. On the other hand, an increase in the passage length requires the honeycomb-shaped deodorant or the like to be formed in a larger size.
Besides, these air treatment systems have been large and complicated in construction because they are composed of two members, namely, a fan member and the honeycomb-shaped deodorant o the like.
Secondly, where the impeller itself of a sirocco fan or axial fan is formed of a deodorant or the like having an air-treating function, an improvement in the air-treating function per unit volume of the impeller can be accomplished by various methods, for instance, by increasing the number of vanes or the length of vanes so as to prolong the dwell time of air. In this case, the passage resistance between the vanes is increased, with the attendant great reduction in the air flow rate across the fan. It is therefore necessary to contrive a higher fan capacity by an increased rotational frequency, an increased fan size or the like.
As a result, these air treatment systems have been accompanied by the problem of noise due to an increased rotational frequency or the problem of a large fan size.
It is accordingly an object of this invention to provide a process for air treatment by a multi-stacked rotatable plate assembly which is capable of solving the above-mentioned problems associated with the conventional types of air treatment systems.